Compression tool



Sept. 19, 1967 M. F. TEPNER COMPRESSION TOOL 2 Sheets-$heet 2 OriginalFiled June 17 FIG 7 R m N W m MARVIN F TEPNEP United States PatentOfiice 3,342,056 Patented Sept. 19, 1967 3,342,056 COMPRESSION TOOLMarvin F. Tepner, Plainview, Nebr. 68769 Original application June 17,1963, Ser. No. 288,121, new Patent No. 3,235,651, dated Feb. 15, 1966.Divided and this application June 21, 1965, Ser. No. 465,468

4 Claims. (Cl. 72-316) This application is a division of my copendingUnited States patent application Ser. No. 288 121, filed June 17, 1963,now Patent No. 3,235,651, granted Feb. 15, 1966.

This invention relates to improvements in making branch connections toplastic conduits, and more specifically to a compression tool for use ininstalling a pressure bypass connection to a plastic-sheathed telephonecable to enable the conduit to be pressurized.

It has long been realized that gas pressurization of telephone cables ishighly desirable to protect such cables against shorting caused bymoisture leaking into the cable. Normally, dry gas under a pressure ofl0 p.s.i. is introduced into a cable to place the cable at a higherinternal pressure than ambient to prevent the entry of moisture throughany cracks or openings in the cable sheath or casing that may exist.

In a typical telephone system the gas is introduced into the cables atthe central station of the system. The cables extend from the centralstation to all of the telephones serviced by the system. At intervalsthe cable is brought to a pedestal and the casing is stripped from asection of the cable to expose the telephone wires so that serviceconnections may be made thereto. The cable casing is sealed at each endof the exposed section in order to make the cable pressure tight. Inorder to maintain the entire cable at a superatmospheric pressure, apressure bypass connection must then be made to the sealed ends of thecable casing in the pedestal to bypass the exposed section so that thepressurized gas can flow from the central station through the entirecased portion of the cable.

The great bulk of telephone installations in this country utilizelead-sheathed cable, and various means have been devised to connect thebypass connections to the lead sheaths of the cables so that the cablesystems could be pressurized. Developments in recent years haveintroduced diiferent variations in cable construction; for example,paper-insulated conductors in plastic-sheathed cables andplastic-insulated conductors encased in plastic-sheathed cables. It hasbeen desired to use these plastic-sheathed cables in a pressurizedsystem, but the major difliculty has been that, in spite of variousattempts, no way has been devised to make satisfactory fieldinstallations of the necessary pressure bypass connections to therelatively thin plastic sheaths of such cables.

It is the primary object of this invention to provide a compression toolfor use in making pressure bypass connections to plastic-sheathedtelephone cables.

A further object is to provide a compression tool for making bypassconnections for plastic-sheathed telephone cables so that the connectioncan be made without the use of heat or solvents which might bedeleterious to the cable, and without decreasing the strength of thecable.

Other objects and advantages will become apparent in the course of thefollowing detailed description.

In the drawings forming a part of this application, and in which likeparts are designated by like reference numerals throughout the same,

FIG. 1 is a generally schematic illustration of a tele* phone systemutilizing the pressure bypass connection of the invention.

FIG. 2 is a longitudinal sectional view of a portion of a telephonecable and a connection thereto made with the use of a tool embodying theprinciples of the invention,

in which the thickness of various portions of the telephone cable havebeen exaggerated for purposes of illustration.

FIG. 3 is a section view of the telephone cable and connection taken online 3-3 of FIG. 2.

FIG. 4 is a top view of the compression tool used in making the bypassconnection.

FIG. 5 is a sectional view of the tool illustrated in FIG. 4, taken online 5-5 thereof.

FIGS. 6 and 7 are side views of the tool illustrated in FIG. 4, showingthe operating positions of the compression member of the tool.

Referring now to the drawings, wherein is illustrated a preferredembodiment of the invention, FIG. 1 shows a typical telephoneinstallation utilizing the pressure bypass connections of the invention.A plastic-sheathed telephone cable 10 is connected to the switchboard 11at the central station 12 and extends from the station under the ground13 to a pedestal 14. The cable is brought up into the pedestal, and thecable sheath or casing is stripped away to expose the telephone wires inthe cable so that the proper pair can be connected to a telephone 15.The cable 10 then extends underground to the next pedestal 16, whereinthe telephone wires are again exposed so that a service connection canbe made to telephone 17. The cable 10, of course, then extends to all ofthe other telephones serviced by the cable.

In each pedetal, the exposed ends of the cable sheath are sealed in awell-known manner at 18, by epoxy resin or the like, to prevent moisturefrom entering the sheathed portions of the cable. As Will be apparent,the cable 10 is thus comprised of a series of sheathed portionsextending between the central station and the succeeding pedestals.

The sealed ends of the cables are placed in internal pressurecommunication in each pedestal by means of the tubings 19, which connectto the bypass inserts, generally shown at 20, secured to the plasticsheath of the cable.

A tap connection 21 to the cable is provided at the central station toenable pressurized gas from source 13 to be introduced into the interiorof cable 10. The pressure of this gas will be communicated through theinterstices between the telephone wires in the cable and through thebypass tubings 19 to pressurize the entire system. Once pressurized,there will be no gas flow through the cable, but a static pressure willexist therein. Even if one or more small pin-point leaks in the cableshould exist, the minimal flow of gas therefrom would not be suificientto cause the system to lose its protective pressure as long as thesource 13 supplies sufiicient make-up pressure.

The bypass connection The construction of the cable 10 is best shown inFIGS. 2 and 3. As will be seen, the cable 10 is a standard telephonecable, and comprises an outer resilient plastic sheath or casing 26. Aplurality of insulated telephone conductors 27 are carried Within thecasing 26 and are all wrapped together in a tough plastic film 28,typically Mylar. The diameter of the casing 26 is determined by thenumber of telephone conductors carried by the cable. For a 25-paircable, the outer diameter of the casing is in the order of one-half inchand the casing thickness is in the order of inch.

The bypass inserts 20 comprise a core member 30, shown in FIGS. 2 and 3,having an elongated shank 31 r provided with a flow passage 32therethrough and formed with an enlarged flange 33 at one end thereof.This flange is curved, with a radius of curvature essentially equal tothe radius of curvature of the inner surface of the casing 26. A smallrib 34 is formed on and around the upper surface of the flange adjacentthe edge thereof. The core member is preferably formed from a suitablecopper alloy. The flange of the core member sits between the plasticfilm 28 and the casing 26 with the upper surface of the flange in fullcontact with the inner surface of the casing. The shank 31 extendsoutwardly from the casing through a hole 35 in the casing.

A deformable packing member 37, shown in FIGS. 2 and 3, is preferably ofrectangular shape with a central hole 38 therethrough to enable thepacking member to fit onto the shank 31 of the core member and be incontact with the outer surface of casing 26. The packing member 37 maybe of rubber, plastic, leather, or the like.

A generally rectangular retaining band 40, preferably formed from asuitable copper alloy, is provided with a central hole 41, for thereception of shank 31 of the core member 30, and end holes 42. Theretaining band extends circumferentially around the casing 26, and istightly secured in place by rivets 43. This band serves to restrain anycircumferential expansion of the cable in the vicinity of the bypassconnection when the system is pressurized.

An outer tubular member 45 is telescoped onto the shank 31 of the coremember 30, and has an enlargeddiameter flange 46 on one end thereof. Theflange 46 is curved so that the lower surface of the flange conforms tothe curvature of the outer surface of the casing 26. The member 45 ispreferably formed from a suitable copper alloy.

As best seen in FIG. 2, the upper end of shank 31 of the core member 30projects from the outer member 45 and is bent at 47 at a point spacedfrom the upper shoulder 48 of the outer member. The resilient plasticbypass tubing 19 is telescoped onto the exposed end of the shank 31 andis stopped by the upper shoulder 48 of the outer member. The tubing 19is held in place by a retaining ring 50 which is disposed about thetubing and located between the outer member 45 and the bend 47 in theshank 31.

The plastic film 28 is perforated at 51 adjacent the passage 32 throughthe core member 30 so that the bypass tubing 19 is in pressurecommunication with the interstices between the telephone wires 27.

Compression tool 7 The compression tool 57, illustrated in FIGS. 4-7,comprises a pair of elongated handle members 81 and 82 pivotally joinedtogether at their ends by links 83 and pins 84. Both handles have headportions adjacent the pivotally connected ends of the handles providedwith top surfaces 86 and 87 and side surfaces 88 and 89, respectively.

The side surface 88 of handle 81 has a semi-circular groove 91 formedtherein extending from the top surface 86, and a similar groove 92 isformed on handle 82. These grooves are knurled or otherwise roughened,and when the handles 81 and 82 are closed together the grooves form acircular hole of slightly smaller diameter than the diameter of theshank 31 of the core member 30 so that the shank can be securely grippedby the tool 57.

Handle 81 carries a locking ring 93 at the end thereof which is adaptedto encompass the adjacent end of handle 82, as seen in FIG. 6, to lockthe handles in closed position.

An elongated compression member 95 is disposed on the top surface 87 ofhandle 82, and is held in place thereon by link 96 and screws 97 and 98,which connect to the compression member and handle, respectively. Theholes in link 96 which accommodate screws 97 and 98 are slightlyoversize to provide suflicient lost motion to enable the compressionmember 95 to rock on the handle 82.

As best seen in FIG. 6, the compression member 95 has a transverseshoulder 1 adjacent one end thereof which rests on the upper surface 87of handle 82. The other end of the compression member has a portion 102on the lower surface thereof normally resting on the upper surface 87 ofhandle 82, and is provided with an upwardly extending cam surface 103extending generally from 102 towards the upper surface 104 of thecompression member.

Intermediate the ends thereof, the compression member is provided with ahole 105 therethrough of slightly larger diameter than that of the shank31 of the core member. When the compression member contacts the uppersurface 87 of the handle 82, hole 105 is in axial alignment with thehole formed by grooves 91 and 92 when the handles are closed.

A lever arm 107 is pivotally connected by bolt 108 to the upper sunface86 of handle 81, and has a handle portion 109 formed on one end and asloping wedge surface 110 formed on the other end thereof. When thehandles 81 and 82 are closed together, counterclockwise rotation oflever arm 107 will force the wedge surface 110 thereof between the uppersurface 87 of handle 82 and the cam surface 103 of the compressionmember 95 to rock the compression member in a clockwise direction aboutits shoulder 101, as shown in FIG. 7. An upwardly extending stop member111 on handle 81 is provided to engage handle 109 and limitcounterclockwise rotation of the lever arm.

When the compression member 95 has been rocked to its position shown inFIG. 7, it will be noted that the axis of compression member hole 105 isinclined at an angle to the axis of the hole formed by grooves 91 and92.

Method of installation of a bypass Insert To install a bypass insert ina telephone cable in accordance with the invention, the hole 35 in thecasing is first made, by use of a casing cutter. The casing is thentemporarily stretched within the plastic memory of the casing adjacentthe hole to enlarge a diameter of the hole so that the enlarged-diameterflange 33 of the core mem ber 30 can be inserted through the hole 35.The plastic material used in the casing 26 can be temporarily stretched,but the inherent memory of the material will cause it to creep backgradually to resume its original unstretched shape. Several punctures 51are made in the plastic film 28 to ensure adequate pressure communication between the interior of film 28 and the casing 26. If desired,this step can be performed before the last-described step of stretchingthe casing.

The flange 33 of the core member is then worked through the temporarilystretched hole 35, leaving the shank 31 projecting from the hole. Theshank 31 is positioned so that the curved flange 33 is in full surfacecontact with the inner surface of the casing, i.e., with the axis of thecurvature of flange 33 being coaxial to cable 10. Although this positionis easy to determine by feel, an index mark could be made on the shank31 to indicate the position of the flange 33. The mechanical pressurebetween the conductors and the cable casing will then hold the coremember in proper position to permit the following steps to be made.

In the event that a different-size cable is to be Worked upon, adifferent core member 30 will be used having a flange curvature equal tothe inner curvature of the casing.

The packing member 37 is then put into place in contact with the outersurface of the casing, with the shank 31 projecting through the packinghole 38.

The retaining band 40 is then wrapped around the casing and the endsthereof are secured by n'vets 43- to grip the casing tightly.

The outer member 45 is then telescoped onto the shank 31 and ispositioned on the retaining band so that the curved lower surface of theflange 46 is in full contact with the retaining band. The curved flangesof the outer member 45 and the core member 30 will now be inparallelism. It is of course to be appreciated that if a different coremember is used on a different sized cable, a dif ferent outer memberhaving a correspondingly differ- 75 ent curvature of its flange will beused. The normal inner diameter of the member 45 is just slightlygreater than that of shank 31 so that the member 45 fits easily thereon.

By this time, the memory of the plastic casing will have caused thecasing to return from its temporarily stretched condition to itsoriginal shape and the casing will be in contact with the shank 31completely therearound.

The compression tool 57 is now used. The lever arm 107 is rotated sothat the wedging surface 110 thereof is out of the way of thecompression member 95. The handles 81 and 82 are opened, and the tool ismanipulated so that the shank 31 extends through the compression memberhole 105 and the upper surface 104 of the com pression member 95 abutsthe end 48 of the outer member. Handles 81 and 82 are then closed togrip the end of shank 31 by the roughened grooves 91 and 92. The lockingring 93 is slipped over the end of handle 82 and into groove 112 to lockthe handles together.

With the handles held still, the lever arm 107 is then rotated intoengagement with the stop member 111 to move the wedging surface 110thereon into engagement with the cam surface 103 of the compressionmember to force the compression member away from the handle 82. Sincethe shank 31 is gripped by handles 81 and 82, and since the outer member45 is abutted by the upper surface of compression member 95, the shankand outer members will be forced in opposite directions to force theflanges thereon together. The casing 26 will thus be very tightlygripped between the flanges 33 and 46. A very effective seal is formedboth by the high compressive pressure between the flanges and by meansof the rib 34 on the upper surface of flange 33 which embeds itself intothe casing wall. Additionally, the compressive force between the flangeswill cause the deformable packing member 37 to flow somewhat towards thecore member and into effective sealing engagement between the coremember and the outer member 45.

Although it is preferable to use the deformable packing member 37 formaximum sealing, effective sealing can still be obtained if this elementis omitted. The plastic casing 26 itself is deformable and thecompression of the casing between the flanges 33 and 46 will cause thecasing to deform therebetween, tending to reduce the diameter of thecasing hole 35 so that the casing flows into sealing contact with theshanks of the core member and the outer member 45. The rib 34 on theupper surface of the core member flange 33 assists in this operation,since it aids in preventing the compressed casing between the flangesfrom flowing outwardly from the casing hole 35.

An important aspect of the compression step is that the core member andouter member are subjected only to longitudinal movement and that thereis no relative rotation therebetween. Relative rotation must be avoided,since otherwise the curved flanges 33 and 46 would not be in parallelismafter compression, and they would not compress the casing equally aroundthe shank 31, thereby preventing an effective seal.

At the same time that the flanges are compressed together, thecompression tool 57 will produce bend 47 in the shank 31, due to thefact that the compression member hole 105 becomes angularly inclined tothe hole formed by grooves 91 and 92.

Since the amount of rocking movement of the compression member 95 isdependent solely upon the thickness of the wedging surface 110 of thelever arm I107, it is apparent that the amount of compression in eachinstallation of a bypass insert will be the same to produce uniformresults.

With the core member and outer member held in compressed position by thecompression tool 57, the outer member is clamped onto the core member bya standard tool such as a Nicopress tool. Inasmuch as this is a standardtool, the details thereof have not been illustrated. Nicopress tools aremade by The National Telephone Supply Co. of Cleveland, Ohio, and aredescribed in U.S.

Patent No. 2,086,400. For the purpose of'this disclosure, it issufiicient to state that the jaws of such toolsurround the outer member,and when the jaws are closed, it will squeeze the outer member, forminglongitudinal wings 116 thereon, as best seen in FIG. 3, which has theresult of decreasing the inner diameter of the outer member 45 so thatit grips the shank 31 of the core member with great force.

With the outer member 45 clenched tightly to the core member 30, thecompression tool 57 is unlocked and removed.

A retaining ring 50 is then slid onto the end of the bypass tubing 19,and the tubing is telescoped onto the exposed end of the shank 31. Thering 50 is then slid down on the tubing, past the bend 47 in the shank,and is positioned between the outer member 45 and the shank bend 47. TheNicopress tool is then used to clench the retaining ring 50 securelyonto the tubing 19 by reducing the inner diameter of the ring, formingthe excess metal into wings 117.

Since the tubing 19 is formed of resilient plastic, the retaining ringwill not form as effective a mechanical connection as is formed betweenthe outer member 45 and core member shank 31. However, the bend 47 inthe shank will provide a mechanical lock for the retaining ring 50,since after the reduction in the inner diameter of ring 50 it can nolonger slide past the bend in the shank without the application of amuch greater force than will exist when the system is subjected to theintended superatmospheric pressure.

It may be desired in some instances to thread the end of shank 31 sothat the bypass tubing 19 might be connected thereto by a standard nutconnection. In such an event, the threaded end of shank 31 would have tobe sufiiciently spaced from the outer member 45 so that the threads arenot damaged by the roughened grooves of compression tool 57.

It will be apparent from the above that the bypass connection describedherein can be easily made in the field with the compression tool 57described herein.

The pressure bypass connection is purely a mechanical connection, andmay be put to use immediately. No heat is applied, as might beencountered in a vulcanizing process, and thus any damage that might becaused to the cable through heating is avoided. No solvents are usedwhich might be injurious to the cable or the insulation of the wireswithin the cable, and of course the delay that would be encountered inwaiting for solvents to set is avoided.

It is to be realized that the form of the compression tool that isillustrated and described herein is a preferred embodiment of theinvention, and that various changes may be made in the shape, size andarrangement of the parts thereof without departing from the spirit ofthe invention or the scope of the attached claims.

Having thus described my invention, what I claim is:

1. A compression tool comprising:

a pair of handle members, each having a top surface and a side surface,

means pivotally connecting said handle members for movement of said sidesurfaces into and out of abutment with each other,

said side surfaces each having a roughened groove extending from saidtop surfaces to form a hole through said handle members when said sidesurfaces are in abutment,

means for locking said handle members together with said side surfacesin abutment with each other,

an elongated compression member mounted on the top surface of one ofsaid handle members for rocking engagement with said handle member aboutone end of said compression member,

means for forcing the other end of said compression member from a firstposition adjacent said handle member to a second position away from saidhandle member,

said compression member having a hole therethrough intermediate itsends, said compression member hole being in axial alignment with saidhandle members hole when said compression member is in its firstposition.

2. A compression tool as set forth in claim 1 and further including stopmeans for limiting the amount of movement of said other end of saidcompression member away from said handle member.

3. A compression tool comprising:

a pair of elongated handle members, each having a top and side surfaceadjacent one end thereof,

means pivotally connecting said handle members at said one end thereofto enable said side surfaces to be moved into and out of abutment,

said side surfaces each having a roughened groove extending from the topsurface, said grooves forming a circular hole when said side surfacesare in abut ment,

means for locking said handle members together when said side surfacesare in abutment,

an elongated compression member mounted on the top surface of one ofsaid handle members, said com pression member being in contact with saidtop surface adjacent each end of said compression member, saidcompression member having a sloping cam sur face on one end thereoffacing said top surface, said compression member having a holetherethrough intermediate its ends in axial alignment with the holeformed by said head portion when in abutment, said compression memberhole having a cross-section longer than said head portions hole;

a lever arm rotatably mounted on one of said handle members, said armhaving a wedge surface thereon movable between said compression membercam surface and said top surface adjacent thereto to rock saidcompression member on said top surface about the point of contacttherebetween adjacent the other end of said compression member to movethe holes in said compression member and said handle member away fromeach other and into angular relationship with each other.

4. In a tool as set forth in claim 3, and further including stop meanson one of said handle members for limiting the rotation of said leverarm.

References Cited UNITED STATES PATENTS 1,042,404 10/ 1912 Coutant 72-4102,172,351 9/1939 Kivley et a1. 72-409 2,440,040 4/ 1948 Burton 72410 X2,732,744 1/1956 Kuchm'an et al 72-409 X RICHARD J. HERBST, PrimaryExaminer.

E. SUTTON, Assistant Examiner.

1. A COMPRESSION TOOL COMPRISING: A PAIR OF HANDLE MEMBERS, EACH HAVINGA TOP SURFACE AND A SIDE SURFACE, MEANS PIVOTALLY CONNECTING SAID HANDLEMEMBERS FOR MOVEMENT OF SAID SIDE SURFACES INTO AND OUT OF ABUTMENT WITHEACH OTHER, SAID SIDE SURFACES EACH HAVING A ROUGHENED GROOVE EXTENDINGFROM SAID TOP SURFACES TO FORM A HOLE THROUGH SAID HANDLE MEMBERS WHENSAID SIDE SURFACES ARE IN ABUTMENT, MEANS FOR LOCKING SAID HANDLEMEMBERS TOGETHER WITH SAID SIDE SURFACES ABUTMENT WITH EACH OTHER, ANELONGATED COMPRESSION MEMBER MOUNTED ON THE TOP SURFACE OF ONE OF SAIDHANDLE MEMBERS FOR ROCKING ENGAGEMENT WITH SAID HANDLE MEMBER ABOUT ONEEND OF SAID COMPRESSION MEMBER, MEANS FOR FORCING THE OTHER END OF SAIDCOMPRESSION MEMBER FROM A FIRST POSITION ADJACENT SAID HANDLE MEMBER TOA SECOND POSITION AWAY FROM SAID HANDLE MEMBER, SAID COMPRESSION MEMBERHAVING A HOLE THERETHROUGH INTERMEDIATE ITS ENDS, SAID COMPRESSIONMEMBER HOLE BEING IN AXIAL ALIGNMENT WITH SAID HANDLE MEMBERS HOLE WHENSAID COMPRESSION MEMBER IS IN ITS FIRST POSITION.